<p class="ql-block">二零二二年十一月十二日</p><p class="ql-block">在天線設(shè)計中，最難的是控制方向圖。因為方向圖是由電流在空間的幅度，相位及極化所決定的。此文，通過reactive impedancesurface對近（不規(guī)則）地電磁場的控制，實現(xiàn)對遠(yuǎn)區(qū)輻射場的調(diào)控。應(yīng)用場景是WLAN AP天線的全覆蓋。</p> <p class="ql-block">二零二二年六月十五日</p><p class="ql-block">二個學(xué)生（DR SU YUANYAN and DR XU RUOLEI） 一條龍式的探索。期待著進(jìn)一步完善設(shè)計方法，早日為工程所用。</p><p class="ql-block">圖一：用PCB實現(xiàn)了平面三維龍伯天線設(shè)計與加工。</p><p class="ql-block">圖二：提出沿徑向平面化的變換光學(xué)法及全模式龍伯天線設(shè)計。</p><p class="ql-block">圖三：提出完整變換光學(xué)法模型及平面龍伯天線設(shè)計。</p><p class="ql-block">圖四：基于完整變換光學(xué)法模型設(shè)計的零焦距龍伯天線。</p><p class="ql-block">1. Y. Su and Z. N. Chen, "A Flat Dual-Polarized Transformation-Optics Beamscanning Luneburg Lens Antenna Using PCB-Stacked Gradient Index Metamaterials," in IEEE Transactions on Antennas and Propagation, vol. 66, no. 10, pp. 5088-5097, Oct. 2018, doi: 10.1109/TAP.2018.2858209.</p><p class="ql-block">2. Y. Su and Z. N. Chen, "A Radial Transformation-Optics Mapping for Flat Ultra-Wide-Angle Dual-Polarized Stacked GRIN MTM Luneburg Lens Antenna," in IEEE Transactions on Antennas and Propagation, vol. 67, no. 5, pp. 2961-2970, May 2019, doi: 10.1109/TAP.2019.2900346.</p><p class="ql-block">3. R. Xu and Z. N. Chen, "A Transformation-Optics-Based Flat Metamaterial Luneburg Lens Antenna With Zero Focal Length," in IEEE Transactions on Antennas and Propagation, vol. 70, no. 5, pp. 3287-3296, May 2022, doi: 10.1109/TAP.2021.3137528.</p><p class="ql-block">4.R. Xu and Z. N. Chen, "A Hemispherical Wide-Angle Beamsteering Near-Surface Focal-Plane Metamaterial Luneburg Lens Antenna Using Transformation-Optics," in IEEE Transactions on Antennas and Propagation, vol. 70, no. 6, pp. 4224-4233, June 2022, doi: 10.1109/TAP.2021.3138554.</p> <p class="ql-block">二零二二年五月三日</p><p class="ql-block">R. Xu and Z. N. Chen, "A Hemispherical Wide-Angle Beamsteering Near-Surface Focal-Plane Metamaterial Luneburg Lens Antenna Using Transformation-Optics," in IEEE Transactions on Antennas and Propagation, June 2022</p><p class="ql-block">前一篇工作關(guān)于光學(xué)變換在Luneberg lens設(shè)計中正確應(yīng)用的理論討論（姊妹篇）。這是一個設(shè)計的驗證，即，在對經(jīng)典圓球Luneberg lens進(jìn)行平面變換時將透鏡的焦點保持在被壓縮的平面上的設(shè)計。在這之前的設(shè)計都無法做到這點。而這點在天線設(shè)計中是非常重要的。否則，焦點遠(yuǎn)離天線的總體積并沒有被明顯壓縮，透鏡自身的反射很大，以及透鏡的掃描角度被大大的壓縮了。</p> <p class="ql-block">二零二二年四月三十日</p><p class="ql-block">R. Xu and Z. N. Chen, "A Transformation-Optics-Based Flat Metamaterial Luneburg Lens Antenna with Zero Focal Length," in IEEE Transactions on Antennas and Propagation, doi: 10.1109/TAP.2021.3137528.</p><p class="ql-block"><br></p><p class="ql-block">圖片是用來驗證平面化的二維luneberg透鏡。</p><p class="ql-block"><br></p><p class="ql-block">這個工作從變換光學(xué)在luneberg透鏡平面化設(shè)計中的應(yīng)用出發(fā)，研究了如何正確應(yīng)用TO的方法。第一次成功地將饋源保持在TO變換后的luneberg透鏡表面上。</p><p class="ql-block"><b>Abstract:</b>The transformation-optics (TO) technique has been widely applied in the volume reduction of Luneburg lens (LL) in both optical and microwave regimes. However, it is found that the focus is usually not located on the surface of the transformed LL anymore after applying TO. The focus location shift results in a limited volume reduction, severe reflection from the new lens surface, and limited scanning range with increased spillover loss. This paper theoretically studies and proposes a TO-based LL antenna with zero focal length by considering the phase mismatch caused by the space discontinuity. The study first reveals that the transformation of an LL alone without sustaining the original boundary inherently deteriorates the original focusing property even before exerting any approximation. To validate the idea, a flat metamaterial LL antenna using TO is proposed, approximated, and fabricated using an integrated dielectric and conductive three-dimensional printing manufacturing process. The feeding patch antenna remains on the surface of the transformed lens. The thickness of the proposed antenna is reduced to 1/3 of a traditional LL in its boresight, while a ±20° beam scanning range is achieved with linearly shifted feedings. The study verifies that it is essential to ensure phase matching at the radiation boundary to maintain the original focusing property of an LL. The information derived from the study evidences the conditions of the enforcement of the TO in electromagnetic problems such as dielectric lenses.</p> <p class="ql-block">二零二二年四月三十日</p><p class="ql-block">R. Xu and Z. N. Chen, "A Compact Beamsteering Metasurface Lens Array Antenna With Low-Cost Phased Array," in IEEE Transactions on Antennas and Propagation, vol. 69, no. 4, pp. 1992-2002, April 2021, doi: 10.1109/TAP.2020.3026905.</p><p class="ql-block">phased array具有強(qiáng)大的波束形成和掃描功能，是個非常棒的天線技術(shù)?，F(xiàn)在已經(jīng)成為高端天線系統(tǒng)中的標(biāo)配。然而，phased array的天線饋電網(wǎng)絡(luò)與相移的復(fù)雜性使得系統(tǒng)的成本與功耗一直都是非常挑戰(zhàn)的。該文利用metalens array來減少phase shifter的數(shù)量和以及透鏡帶來的天線厚度。從天線架構(gòu)和metalens的應(yīng)用上有所突破。拋磚引玉，期待業(yè)界能夠在系統(tǒng)樣機(jī)方面有所推進(jìn)。</p><p class="ql-block"><br></p><p class="ql-block">該工作已經(jīng)幾次獲學(xué)生論文競賽獎，并應(yīng)邀在三大社交媒體上分享。根據(jù)Xplore （IEEE TAP），迄今為止，已有3098次 full text views。</p><p class="ql-block"><b>Abstract: </b>A metasurface (MTS) lens array (MLA) fed by a phased array with less phase shifters (PSs) is proposed for compact low-cost beamsteering applications. By dividing a single-large-aperture lens into N small-aperture lens elements with the focus-to-diameter ratio of a lens antenna unchanged, the overall thickness of the proposed antenna is reduced by N times. The beamsteering is achieved in two steps. First, the main beam direction of MLA antenna is switched over a large angular step by shifting the feeding antennas beneath each lens element. Then, the switched beams are fine steered by a low-cost N-element phased array. Theoretical analysis using array theory is performed to work out a general design method with discussion on the taper and spillover effect of feed-power pattern on the lens array. Based on the proposed method, a three-lens linear MLA fed by a phased array is designed to operate at 10 GHz. The proposed antenna achieves a 3 dB beamwidth coverage range of ±30° with a beam crossing level higher than -3 dB and a gain tolerance of 1.6 dB with a maximum gain of 19.1 dBi. The presented antenna can be used to achieve volumetric beamsteering performance directly. The proposed design features the merits of higher gain, lower cost, simpler feeding network, less PSs, and lower profile compared with conventional full phased arrays and single-aperture lens antennas.</p> <p class="ql-block">二零二二年四月十九日</p><p class="ql-block">DL-Enabled metasurface. 藝術(shù)創(chuàng)作的新時代。????</p><p class="ql-block">這是一個利用先驗知識基于深度學(xué)習(xí)建立起的超表面綜合方法。metalens是用來展現(xiàn)這個方法功效的。</p><p class="ql-block">工作已經(jīng)清楚地顯示，通過深度學(xué)習(xí)綜合的三層metacells，具有了前所未有的設(shè)計自由度（degrees offreedom），為突破現(xiàn)有技術(shù)的中的相移提供了空間。進(jìn)一步，由于這個增大的設(shè)計自由度，極大地豐富了metacell set，為提高metalens的帶寬與增益提供了更大的可能性。</p><p class="ql-block"><br></p><p class="ql-block">更為重要的是，通過這個工作，我們對如何利用深度學(xué)習(xí)，這個復(fù)雜的綜合過程，建立起新的綜合方法有了切身體會。特別是如何target setting，即需要堅實的專業(yè)知識和具體設(shè)計方向的洞察力，有了深刻認(rèn)識。</p><p class="ql-block"><br></p><p class="ql-block">更加深入的思考是如何理解，人與機(jī)器，人與人工智能化機(jī)器的哲學(xué)關(guān)系；工程技術(shù)人員如何在未來強(qiáng)大的智能化機(jī)器社會中生存；以及未來工程研究與應(yīng)用發(fā)展的必然趨勢等。這些似乎更加一般性的問題，確實是個值得盡早思考的問題。</p><p class="ql-block"><br></p><p class="ql-block">根據(jù)我有限的經(jīng)驗和知識，我預(yù)感，深度學(xué)習(xí)在工程，比如在天線設(shè)計上，不僅僅是優(yōu)化，不是一個選項，而是一個必須。而這種發(fā)展，呼喚著也依賴著行業(yè)大師（domain master）的投入。</p><p class="ql-block"><br></p><p class="ql-block">我正在拭目以待一個天線設(shè)計新紀(jì)元的到來。</p> <p class="ql-block">Latest updated on 6 Aperil 2022</p><p class="ql-block">上一次update是二年前。二年來，我們的metantenna研究已經(jīng)有了許多新的有趣的工作。特別是對What's next有了一些想法。</p><p class="ql-block">我以為，Metasurfaces在天線技術(shù)研究中有三個重要工作（請見我們最近在EUCAP2022上的分享）：</p><p class="ql-block">一，MTS自身的理論及功能研究;</p><p class="ql-block">二，新的模型，優(yōu)化和綜合方法的研究與應(yīng)用;以及</p><p class="ql-block">三，提高現(xiàn)有技術(shù)的性能上限及增加新的功能。</p><p class="ql-block">過去幾年，充分利用現(xiàn)有的有限資源，我們一直都在這三個主方向上攻城，但是不掠地。</p> <p class="ql-block">新應(yīng)用：phased arrays</p><p class="ql-block">新方法新應(yīng)用：Characteristic Mode Analysis</p><p class="ql-block">新方法新邊界：Deep Learning</p> Metantennas <p class="ql-block"><span style="color:rgb(1, 1, 1);">what is an antenna?</span></p><p class="ql-block"><span style="color:rgb(1, 1, 1);">A: A piece of simple metal but highly complex tasks.</span></p><p class="ql-block"><span style="color:rgb(1, 1, 1);">A: An artswork!</span></p><p class="ql-block"><span style="color:rgb(1, 1, 1);">A: A magic!</span></p> <h3><font color="#010101">As promised, I will selectively introduce part of our antenna work based on magic metamatetials. Before reading this introduction, suppose you have known the concept of metamatetials very well and agreed with my understanding of metamaterials with three key features from enclosed link. Otherwise, we don't have common sense to discuss the issues here.<br><br>http://a.meipian.me/1kugkm8?from=groupmessage&isappinstalled=1<br><br>遵守承諾，我會逐步介紹目前我們基于電磁泛材料所發(fā)展的天線技術(shù)。不過在此之前，希望你已經(jīng)十分了解電磁泛材料的概念，并認(rèn)可我對電磁泛材料三大要素的理解。否則，我們就失去了討論問題基點，雞同鴨講了。
http://a.meipian.me/1kugkm8?from=groupmessage&isappinstalled=1
這里的想法基本上在工業(yè)界落地了。十分感謝業(yè)界對我的信任，在我們互相完全不認(rèn)識的情形下，冒險投資我的團(tuán)隊。同舟共濟(jì)，共達(dá)彼岸，開創(chuàng)泛材料落地市場的局面?，F(xiàn)在泛材料的概念已經(jīng)滲入到我們?nèi)粘５男绿炀€技術(shù)開發(fā)與設(shè)計中。正在艱苦前行。
一點注釋：
自metamaterials被提起的第一天起，因為它打破了所有現(xiàn)有電磁場中物理概念的藩籬，非常自然地引起了許多爭論。這種爭論既是正常的，更是有益的。它大大地促進(jìn)了該理論的發(fā)展與完善。
另一方面，在工程界也有很大的爭議，而且這種爭議并沒有隨著越來越多的應(yīng)用的出現(xiàn)而減弱。原因不外乎，一是對概念，其實更多的是對表述上的不認(rèn)可。二是還是缺乏的工程上成功的范例。三是沒有分清科學(xué)和工程語言上的微妙區(qū)別。四是把物理概念等同于工程技術(shù)。五是沒有機(jī)會真正搞明白那個概念，而是靠想像或所謂的直覺去理解。六是因為圈里的一些不實或泛美之詞甚至一些學(xué)術(shù)界的江湖騙子的不齒所為。
我以為，作為工程技術(shù)研究人員的我們，最重要的是要努力明白科學(xué)語言和物理概念，然后努力把對物理概念的抽象的理論描述的科學(xué)語言轉(zhuǎn)換成可設(shè)計的工程技術(shù)參數(shù)，從而架起應(yīng)用與理論的橋梁。
另外，在講述和推銷這個概念時一定要客觀，要分清你在和誰說話。在“忽悠”研究基金時，你可以也應(yīng)該畫一張夢幻之圖，編一些新名詞和時髦的術(shù)語，讓大家憧憬。作為科學(xué)研究，就是去探索未知，就是要展開想像的翅膀。但當(dāng)你談?wù)摴こ碳夹g(shù)時，還是老老實實地把工程上的可行性放在前臺，忘掉那些美妙的名詞，扎扎實實地解決問題，來不得半點虛假。
搞工程技術(shù)的我，從來不參與所謂概念上的爭論，那是搞物理人的事。我曾經(jīng)經(jīng)歷過對MEI方法的爭論，現(xiàn)在的META。對我而言，解決具體問題就是硬道理。一旦將概念成功地轉(zhuǎn)化為技術(shù)，而技術(shù)又被市場采用了，就是真正的成功。至于，新技術(shù)被冠以了META還是TAME重要嗎？
眾所周知，物理概念是工程技術(shù)的基礎(chǔ)。任何一個新的物理概念都有可能會對技術(shù)發(fā)展產(chǎn)生革命性的影響。技術(shù)要創(chuàng)新，就必須密切關(guān)注物理概念的變化與發(fā)展。
<br><br></font></h3> <h3><font color="#010101">Since 1999, metamaterials have been scientifically researched widely. Many excellent scientific findings have covered all spectra. Potential applications have also invovled almost all EM and even physical waves or fields. </font></h3><h3><font color="#010101"><br></font></h3><h3><font color="#010101">I think, the most successful applications of metamaterials have included at least absorbers and antenna radomes in EM fields before 2014. However, we have hardly seen the real industry applications of metamaterial-based antennas although many claims have been in press release. After deeply thinking, I realized that we must find a new way to avoid the two inherent drawbacks of strongly resonant double negative structures for antennas with simple structure, high efficient, and wide enough bandwidth which achieved greatly enhanced performance of interest.</font></h3><div><font color="#010101"><br></font></div><h3><font color="#010101">*More details can be found </font><span style="color: rgb(1, 1, 1);">a</span><span style="color: rgb(1, 1, 1);">t </span></h3><h3><span style="color: rgb(1, 1, 1);">http://www.e-fermat.org (《上海大學(xué)學(xué)報》) </span><span style="color: rgb(1, 1, 1);">a</span><span style="color: rgb(1, 1, 1);">t </span></h3><h3><span style="color: rgb(1, 1, 1);">http://www.journal.shu.edu.cn/CN/article/showArticleBySubjectScheme.do?code=TN%20011 or </span><font color="#010101">http://www.cjors.cn/CN/article/showBrowseTopList.do?year=3（電波科學(xué)學(xué)報2018 Vol.33(3):239-255）.</font></h3><h3><font color="#010101"><br></font></h3><h3><font color="#010101">After deeply thinking, I realized that we must find a new way to avoid the two inherent drawbacks of strongly resonant double negative structures for antennas with simple structure, high efficient, and wide enough bandwidth which achieved greatly enhanced performance of interest.</font></h3><h3><font color="#010101"><br></font></h3><div><font color="#010101">First, let us address the top general challenges of antenna engineering again as follows:</font></div><div><font color="#010101"><br></font></div><div><font color="#010101">1 wide enough operating bandwidth in terms of not only impedance matching but also all performances of interest.</font></div><div><font color="#010101"><br></font></div><div><font color="#010101">2 high enough gain, not only directivity but also radiation efficiency</font></div><div><font color="#010101"><br></font></div><div><font color="#010101">3 simple enough structure or/and low enough cost for ease massive production.</font></div><div><font color="#010101"><br></font></div><h3><font color="#010101">It should be noted that the most challenging issue is that all antenna designs must meet all specifications simultaneously besides the three challenges montioned above, such as beamwidth, mutual coupling, front-to-back ratio, volume, and so on.</font></h3><h3><font color="#010101"><br></font></h3><h3><font color="#010101">In 2010, we officially started our R&D&C of metamaterial-based antennas . Here, I demonstrated some of them to show how we worked out the ideas to apply the physical concepts of metamaterials in developing innovative antenna technologies for commercial applications one by one.
From more and more success stories, you may have realized that
A. the physical concepts of metamaterials have opened a new s for not only the academic research in EM fields but also, more importantly, innovative antenna design, and
B. with the metamaterial-based technologies, the limits of existing technologies, not physical limits, have been broken.<br></font></h3> <h3>Notes on Metamaterials (MTM) vs Metasurfaces (MTS)</h3><h3><br></h3><h3>Conventionally, metasurface is regatded as a two-dimensional version of metamateroal. In genetal. it seems logical if we define all artificial strictures featuring unique electromagnetic properties which have yet found in nature as metamaterials. But the comparison of both shows us the difference between them if we consider metamaterials as three-dimensional uniform/periodic structures. </h3><h3><br></h3><h3>At least two important aspects differentiate them besides the dimension of structures. The one is that the MTM is usually a structure of periodic arrays of elements in three dimensional way which while the MTS is formed with non-uniform arrayed unit cells on a sutface. Certainly, the MTS can be considered as a cross-section of a non-periodic MTM.</h3> TECH21 Metaline based Loop s <p>metaline based loop antenna:一種基于engineered dispersion line的環(huán)天線。通過在單線上的分布式加載，改變單線色散特性的控制，實現(xiàn)不改變頻率的大波長工作狀態(tài)。利用這個特性，可以保證在電大尺寸閉環(huán)天線上電流（駐波）不反轉(zhuǎn)。利用這個特性，可以用來設(shè)計電大尺寸的近場磁耦合天線和遠(yuǎn)場全向輻射天線。 </p> <p><span style="color: rgba(0, 0, 0, 0.9);">Metamaterial is a historic physical concept stemmed from microwave lens antenna design about 80 years ago. in the past two decades, it has been developed significantly. It is very interesting to see how optical researchers developed the concepts with huge number of publications and finally microwave researhers translated the concepts to technology for production in market again. Our team have worked on the translational research on metamaterial-based antenna design--metantennas and successfully applied many of them in products closely working with industry partners. I think this is a right direction of EM metamaterial R&D in future. I I posted the publication list of our papers about metaline based loop antennas. Some of these ideas have been real industry designs and licensed to industry partners for RFID and WLAN antennas. all comments are most welcome. </span></p> Tech20 IEEE TAP:? Metantennas <p>Special Issue of IEEE TAP (March 2020) is about Metamaterials and Metasurfaces. Seven papers coauthored by me have been published. This is another record Special Issue of IEEE TAP (October 2009) about millimeter-wave antennas in which we published five papers. </p><p><br></p><p>This year has been the twentyth year since the concept of new metamaterials was proposed. The investigation of metamaterials has been widely evolved from the double-negative materials to the generalized EM structures having unique EM properties. A large number of excellent theoretical fundings have been published. Fortunately, the research has gone on the way towards applications. In particular, metamaterial-based metantennas have finally been commercialized and applied in more and more engineering systems. </p><p> </p><p>Our team has been ed on R&D&C of metantennas for more than a decade. 風(fēng)斯在下，the collaboration with industry has brought in many challenges for our research while our metantenna technology has greatly enhanced the competition of antenna technology in market. </p> TECH19 Flat Meta Luneburg <h3>To bridge the gap between the physical concepts and engineering technology of metamaterials</h3><h3><br></h3><h3><h3>對波在傳輸系統(tǒng)中的傳播，如果用折射率來描述是從材料角度解釋。如果用色散特性來描述則更加直接。我們在分析零相移線時，用的是后者。</h3><h3><br></h3><h3>一直以來，都有對超構(gòu)的工程與物理的不同解釋角度。因為用了折射率，才有了material的說法。而工程上，用等效的材料特性是無法進(jìn)行直接的工程設(shè)計，還是更依賴散射參數(shù)或色散特性，也是落地metamaterials的方法。后者更具工程設(shè)計意義，而從材料角度解釋則更具一般性，就是本構(gòu)關(guān)系。</h3></h3> <h3>#250 用17層pcb板實現(xiàn)天線<br></h3> <h3>#263 TO是沿著徑向方向，掃描角度更寬</h3> Technology 18（集錦） <h3>IEEE TAP 二月刊出版了。我們的三篇都是metantennas。<br></h3> <h3>Technology 17</h3><h3>Summary of Metasurface Antennas using Characterisatic Mode Analysis</h3> <h3>List I of our relevant publications</h3> <h3>List II of our relevant publications</h3> <h3>TECHNOLOGY 16</h3><h3><br></h3><h3>Title: "Truncated Impedance-Sheet Model for Low-Profile Broadband Nonresonant-cell Metasurface Antennas using Characteristic Mode Analysis”</h3><h3><br></h3><h3>Abstract: A unit-cell-free truncated impedance-sheet model (ISM) is proposed for the modeling and design of low-profile broadband metasurface antennas (MAs) composed of non-resonant unit cells using characteristic mode analysis (CMA). Different with conventional MAs with locally resonant unit cells, the non-resonant unit cells of the proposed MAs only contribute to the grid impedance and the MA operates with the global resonances of the metasurfaces. New measures are also reported to incorporate a higher-order metasurface mode for wideband radiation. A low-profile broadband MA is designed at the 5-GHz WiFi bands for proof of concept. Three modes are excited simultaneously, including a quasi-TM01 mode, a quasi-TM21mode, and a dipole mode. With a size of 0.8λL × 0.8λL × 0.087λL (λL is the wavelength in free space at the lowest operating frequency), the prototyped MA achieves a bandwidth of 45% with |S11| < ?10 dB, boresight gain of 8.5~11.6 dBi, and 3-dB beamwidth of 40?~60?/43?~65? for the E-/H-planes. </h3><h3><br></h3><h3>Published in: IEEE Transactions on Antennas and Propagation</h3><h3>Volume: 66, Issue: 10, Oct. 2018, Page(s): 5043 – 5051.</h3><h3><br></h3><h3>Significances: For the first time, the characteristic mode of a frequency-dispersive impedance sheet is analyzed. New methods proposed for manipulating multiple resonant modes of metasurfaces by non-resonant unit cells led to low-profile multi-mode wideband metasurface antennas.</h3><h3><br></h3> <h3>TECHNOLOGY 15
<br></h3><h3>
Title: “Metasurface-Based Shared-Aperture 5G S-/K-Band Antenna Using Characteristic mode analysis.”
Abstract:
</h3><h3>An S/K-band metasurface-based antenna with a shared aperture is proposed for 5G applications. The metasurface is designed with the dual-band characteristics for two antennas to work in the same aperture without interference. Based on the characteristic mode analysis (CMA), 3×3 metasurfaces are proposed for the S-band radiation. To radiate the K-band electromagnetic wave without blocking, the metasurfaces are discretized by the sub-cell of a square ring and an inner square patch to achieve a frequency selective function. Then, as an example, the microstrip-fed slot is used to drive the metasurfaces at the S-band while an 8×8 substrate integrated waveguide (SIW) slot array antenna between microstrip and metasurface is designed at the K-band. The measurement shows the 10-dB return loss bandwidths of 23.45% and 4.8% and the realized gain of 7.52-10.88 dBi and 21.3-22.4 dBi over the S-band (3.2-4.05 GHz) and the K-band (25.22-26.46 GHz), respectively.</h3><h3>
Published in: IEEE Transactions on Antennas and Propagation (accepted in September 2018)
Significance: Shared aperture antenna for dual-band operation using metasurface and Characteristic Mode Analysis</h3><h3><br></h3><h3><br></h3> <h3><b>TECHNOLOGY 14</b></h3><h3><b><br></b></h3><h3><font color="#167efb">Title</font>: A Dual-Band Metasurface Antenna Using Characteristic Mode Analysis</h3><h3> </h3><h3><font color="#167efb">Abstract</font>:</h3><h3>A compact metasurface based antenna is proposed for dual-band operations. The proposed metasurface is designed on a single-layered substrate including an array of modified 3×3 squared patches. Each of four corner patches is split into four fractional patches while the four edge patches are evolved into Malta crosses and the center patch is scaled. A substrate integrated waveguide (SIW) based Y-junction cavity-fed dualslot drives the metasurface with multiple impedance resonances. Based on the predicted modal behaviors of metasurface using a characteristic mode analysis (CMA), as an example, an antenna operating at three resonant modes at 28 GHz, 33 GHz, and 36 GHz, respectively is designed for the dual-band operation for the coming 5G. The proposed design shows that the measured impedance bandwidths (return loss larger than 10 dB) are 23.7– 29.2 GHz and 36.7–41.1 GHz with the achieved gain of 4.8–7.2 dBi and 8.9–10.9 dBi, respectively. The proposed dual-band antenna features the advantages of low-profile and wideband, suitable for the coming dual-band 5G applications.</h3><div><br></div><div>Published in: IEEE Transactions on Antennas and Propagation (Early Access/Oct 2018 Issue)</div><h3><br></h3><h3><font color="#167efb">Significance</font>: Shared aperture antenna for dual-band operation using metasurface and Characteristic Mode Analysis</h3> <h3><b><u>二零一八年八月十四日</u></b></h3><h3><br></h3><h3>感謝褚慶昕兄教授的邀請，為《電波科學(xué)學(xué)報》撰稿一篇。匆忙成文，誠請指教!</h3><h3><br></h3><h3>摘要 惠更斯電磁超構(gòu)表面脫胎于現(xiàn)代三維超構(gòu)材料,是一種特殊的二維亞波長陣列結(jié)構(gòu). 基于經(jīng)典電磁學(xué)惠更斯等效原理,惠更斯電磁超構(gòu)表面可以靈活地調(diào)控電磁波的傳播和電磁場的分布,其獨特的電磁特性給天線的創(chuàng)新帶來了巨大的機(jī)遇. 文章將綜述惠更斯電磁超構(gòu)表面在微波天線中的研究進(jìn)展,簡要介紹惠更斯超表面的基本概念和原理并總結(jié)其在微波天線設(shè)計中的應(yīng)用,重點闡述三種惠更斯超構(gòu)表面天線技術(shù)及其設(shè)計案例. 最后,展望惠更斯超構(gòu)表面在天線工程中的廣闊應(yīng)用前景. </h3><h3><br></h3><h3>關(guān)鍵詞 ： 電磁超構(gòu)表面, 超構(gòu)材料, 惠更斯原理, 色散特性分析, 特征模分析, 微波超構(gòu)表面天線, 低剖面寬帶天線, 超構(gòu)表面透鏡天線, 多波束天線, 波束控制, 天線去耦合 </h3><h3><br></h3><h3>Abstract：Based on classic electromagnetic Huygens’ Principle and the concept of modern metamaterials, metamaterial Huygens surface, namely, metasurface (MTS) is presented to be the two-dimensional analogues of metamaterials. With the dense arrays of electrically small unit cells, the MTS can control electromagnetic-waves and fields in either usual or unusual ways. Such unique electromagnetic properties greatly offer additional opportunities to innovate new antennas. This paper updates the latest progress in the MTS based antenna at microwave bands. First, the concept of the MTS is briefly introduced with a summary of applications of the MTS in microwave antenna design. After that, three of selected MTS based antenna techniques are elaborated with design examples. Finally, the promising applications of the MTS in antenna engineering are commented.</h3><h3>Key words： metasurface metamaterial Huygens’ Principle dispersion analysis characteristic mode analysis microwave metasurface antenna low-profile broadband antenna metasurface lens antenna multibeam antenna beam steering antenna decoupling</h3><h3>收稿日期: 2018-05-07 </h3><h3>通訊作者: 陳志寧 E-mail: eleczn@nus.edu.sg </h3><h3>引用本文: </h3><h3>陳志寧，劉煒，李騰，林豐涵，江梅. 惠更斯電磁超構(gòu)表面微波天線的研究進(jìn)展[J]. 電波科學(xué)學(xué)報, 2018, 33(3): 239-255. </h3><h3>CHEN Zhi Ning，LIU Wei，LI Teng，LIN Feng Han，JIANG Mei. Progress in microwave Huygens’ metasurface antennas. Chinese Journal Of Radio Science, 2018, 33(3): 239-255.</h3><h3>鏈接本文: </h3><h3>http://www.cjors.cn/CN/10.13443／j.cjors.2018050701 或 http://www.cjors.cn/CN/Y2018/V33/I3/239</h3> <h3><b>年年年相同，歲歲歲相異。</b></h3><h3><b>無奈時光去，只有快樂留。<br></b><b>癡情麥它謎，戲游天線藝<br></b><b>擁抱戌狗旺，不記酉雞鳴。</b></h3><div><br></div><div>祝大家新年快樂,萬事如意!給大家拜年!</div><div>在過去的二零一七年，我們在metamaterial特別是metasurface antenna的機(jī)理研究，工程設(shè)計與工業(yè)設(shè)計方面有重大進(jìn)展，我甚是欣慰。我會逐步地更新，與大家分享。</div><div>祝大家在新的一年里繼續(xù)努力創(chuàng)新:</div><h1><b><br></b><b>good good study, </b></h1><h1><b>meta meta antenna!!!</b></h1> <h1><b>TECHNOLOGY 13</b></h1><h3><b><br></b></h3><h3>Abstract:
A method is proposed to suppress the unwanted higher-order modes (HOMs) of the metasurfaces in multiport antenna systems for improving the radiation performances using characteristic mode analysis (CMA). The proposed method is to control the modal currents under consideration by loading the unit cells of the metasurface with slots and vias. The positions of loads are determined with the aid of CMA of the metasurface. For proof of concept, the proposed technique is applied to a compact wideband four metasurface antenna system operating at 5-GHz Wi-Fi bands. With the suppression of HOMs, the split and tilted radiation patterns of the metasurface antennas are significantly improved. The concept is experimentally validated for potential compact multiport antenna applications.<b><br></b></h3> <h1><b>TECHNOLOGY 12</b></h1> <h1><b>A Single-layered Spoof-plasmon-mode Leaky Wave Antenna with Consistent Gain</b></h1><h1><b><br></b></h1><div>Abstract— A single-layered leaky wave antenna (SL-LWA) exploiting the groundless spoof plasmons (SPs) structure is presented and validated to achieve consistent scanning beam and broadside gain across a wide bandwidth. The antenna is composed of single-layered meander SP cells and co-planar waveguide (CPW) to SP structure converters. The periodically arranged SP cells of the SL-LWA generate a radiating space harmonic with forward, backward, and broadside radiation against frequency change. The study and experimental validation show that the proposed SL-LWA provides the consistent gain variation less than 2.5 dB of scanning beams within the 10-dB reflection bandwidth of 10.4-24.5 GHz (or 80%). In addition, the proposed antenna offers the wideband broadside radiation with 1-dB gain variation within the frequency range of 16.5-17.2 GHz (or 4.2%). The method to design the antenna operating at desired frequencies is provided. Benefiting from the low-profile compactness and unprecedented performance, the proposed SL-LWA has promising potentials for applications in wireless systems.</div><div> </div><h1><b>Impact of the work</b>:</h1><h1><br></h1><div>Leaky wave antennas (LWAs) with their frequency sweeping beams have found wide applications in frequency scanning radars for simultaneous detection of objects located at various angles.</div><div><br></div><div> Conventional LWAs are suffering from three drawbacks:</div><div><br></div><div> a) low radiating wave generation: LWAs require to be considerably long for a satisfactory radiation.</div><div> b) complex structures: many LWAs are composed of several layers and via holes.</div><div>c) gain variation: the gain of LWAs degrades significantly at higher frequencies</div><div> </div><div> Spoof surface plasmon (SSP) modes are confined surface waves with simple and single layer supporting structures, and easily can be converted to guiding waves.</div><div><br></div><div> </div><div>A new method is proposed to generate travelling waves from SSP modes with high conversion performance using a single-layered leaky wave antenna (SL-LWA) free from ground plane and via holes with a straight-forward design procedure.</div><div><br></div><div><br></div> <h3><b>TECHNOLOGY 11</b></h3> <h3><b>Design of a Near-Field Nonperiodic Zero Phase Shift-Line Loop Antenna With a Full Dispersion Characterization</b>（Published in: IEEE Transactions on Antennas and Propagation ( Volume: 65, Issue: 5, May 2017 )</h3><div>Page(s): 2666 - 2670)</div><div><br></div><div>by Yunjia Zeng, Student Member, IEEE, Zhi Ning Chen, Fellow, IEEE, Xianming Qing, Senior Member, IEEE, and Jian-Ming Jin, Fellow, IEEE</div><div><br></div><div><b>Abstract</b>:</div><div>The tradeoff between the magnetic field distribution, the magnetic field intensity, and the interrogation zone size is one of the most challenging issues in designing a zero phase shift-line (ZPSL) loop antenna for near-field ultrahigh-frequency radio frequency identification (RFID) applications. In this communication, the dispersion characteristics, including phase and attenuation constants, of the ZPSL in a loop configuration are thoroughly analyzed, such that the important design tradeoff can be fully quantified. Based on the dispersion characteristics, a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is proposed. Compared with the periodic configurations, the proposed nonperiodic ZPSL loop antenna shows an improved magnetic field distribution with an enhanced magnetic field intensity.</div><div><br></div> <h3><b>Importance</b>:</h3><div><br></div><div>This work is the good example how to design and optimization of a near-field loop anteena using dispersion characteristics. This work is based on the modeling we developed in Technology 6.</div> <h3><b>TECHNOLOGY 10</b></h3> <h3><b>An Artificial Magnetic Conductor Backed Electrically Large Zero-Phase-Shift Line Grid-Loop Near-Field Antenna</b>（Published in: IEEE Transactions on Antennas and Propagation ( Volume: 65, Issue: 4, April 2017 )</h3><h3>Page(s): 1599 - 1606)</h3><div><br></div><div>by Yunjia Zeng, Student Member, IEEE, Zhi Ning Chen, Fellow, IEEE, Xianming Qing, Senior Member, IEEE, and Jian-Ming Jin, Fellow, IEEE</div><div><br></div><div><b>Abstract</b>:</div><div>A zero-phase-shift line (ZPSL) grid-loop antenna backed by an artificial magnetic conductor (AMC) is proposed to realize a uniform and strong magnetic field distribution over an electrically large interrogation zone for near-field wireless systems. The grid-loop configuration is able to achieve a uniform magnetic field distribution over an enlarged interrogation zone by enhancing the magnetic field in the central portion of the ZPSL loop. Moreover, an AMC comprised of four-arm spiral unit cells is designed to back the ZPSL grid-loop antenna for a directional field distribution and enhanced magnetic field intensity. The proposed antenna is exemplified as a reader antenna for ultrahigh frequency near-field radio frequency identification systems. By using an Impinj Speedway reader with an output power of 30 dBm, a 100% detection rate of Impinj J41 tags is achieved up to 90 mm over an interrogation zone of 200 × 200 mm2.</div><div><br></div> <h3><b>Importance</b>:</h3><div><br></div><div>This work is the success story of metamaterial-based antenna. The metamaterial structure features wideband and low loss even for magnetic fields.</div> <h3><b>TECHNOLOGY 9</b></h3> <h3>IEEE Transactions on Antennas and Propagation Volume: 65 Issue: 3 Page(s): 1141 - 1150， April 2017</h3><h3>（http://ieeexplore.ieee.org/document/7805179/）</h3><h3><b><i><br></i></b></h3><div><b><i>'Characteristic Mode Analysis and Metasurface- Based Suppression of Higher Order Modes of a 2×2 Closely Spaced Phased Array' by Ashraf Adam Salih ; Zhi Ning Chen ; Koen Mouthaan</i></b></div><div><br></div><div><b>Abstract</b>:</div><div>This paper studies the design tradeoffs and modal excitation of closely spaced finite-sized ground plane backed phased arrays in the work of characteristic mode theory, and proposes a method to suppress the higher order modes using a metasurface. The characteristic mode analysis also reveals the dominant modes and the excited modes for wideband operation. From the generalized method of moments impedance matrix and N-port network impedance matrix, key parameters are derived for the analysis, such as modal currents, modal radiation patterns, modal significance, modal weighting, modal radiated power, and modal near fields. The analysis includes the broadside and beamsteering radiation of closely spaced bowtie array antennas. The simulated and measured results show that it is essential for the beamsteering to have multiple modes excited simultaneously. By suppressing the higher order modes using the metasurface, the aperture efficiency and the realized gain can be improved for beamsteering cases. This analysis can be extended to a larger array and used to identify array impedance bandwidth performance in scan cases.</div> <h3><b>Importance</b>:</h3><div><br></div><div>This work first applied CMA in a phased array design and first used metasurface to suppress the higher-order mode in phased array design.</div> <h3>TECHNOLOGY 8</h3> <h3><b>Abstract</b>:</h3><h3><br></h3><div>A metasurface (MTS) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA). An MTS radiator formed by a diamond-slotted patch is fed by a microstrip line at its bottom through a slot centered on a ground plane. The CMA is used for the modeling, analysis, and optimization of the proposed antenna in order to reveal the underlying modal behaviors of the MTS and to guide the mode excitation. It is found that an extraordinary quisi-TM30 MTS mode and a slot mode both with wideband broadside radiation are formulated and well excited simultaneously, leading to a broadband operation. Empirical equations are outlined for speeding up design. To verify the concept, a 2×2 array with the overall size of 1.78λ0×1.78λ0×0.07λ0 ( λ0 is the free-space wavelength at 5.5 GHz) is designed and prototyped at 5-GHz Wi-Fi bands. The achieved impedance bandwidth for 10-dB return loss is 31% with the gain of 13–14.5 dBi over the operating bandwidth.</div> <h3>Importance:</h3><div><br></div><div>This work first applied CMA in a metasurface antenna design. This has shown that with aid of CMA, antennas can be designed with optimized performance very quickly.</div> <h3><b>TECHNOLOGY 7</b></h3> <h3>Metamaterial-based Thin Planar Lens Antenna for Spatial Beamforming and Multibeam Massive MIMO</h3><div><br></div><div>by Mei Jiang et al</div><div><br></div><div>Published in IEEE Transactions on Antennas and Propagation. Vol.65, No.2, pp.464-472, Feb 2017</div> <h3>Abstract:</h3><h3><br></h3><h3>A metamaterial-based thin planar lens antenna is proposed for spatial beamforming and multibeam massive multiple- multiple-output (MIMO) systems. The antenna consists of a planar lens and a linear array of receive/transmit elements. To lower the insertion and reflection loss, the lens is formed by the two-layered ultra-thin metamaterial-based surface separated with air and fed by substrate integrated waveguide (SIW)-fed stacked-patch antennas. The effects of the focal-to- diameter (f/D) on the power distribution of the lens are investigated to work out a design method. A planar lens antenna fed with seven elements is, for example, designed to operate at 28-GHz bands. The measured results show that the proposed antenna can achieve a scanning coverage of ±27o with a gain tolerance of 3.7 dB and a maximum gain of 24.2 dBi with an aperture efficiency of 24.5% over the operating bandwidth of 26.6-29 GHz. The lens antenna also features the advantages of compact size, low cost, lightweight, simple feeding network, and easy integration with other circuits for next generation mobile communication and radar systems.</h3><div><br></div><div> </div><div><br></div><div><br></div> <h3><b>Importance:</b></h3><div><b><br></b></div><div><b>This work is the first implemrntation of a planar lens based massive MIMO antenna operating at 28 GHz bands for coming 5G applications.</b></div><div><br></div> <h3><b><font color="#010101">TECHNOLOGY 6</font></b></h3> <h3><font color="#010101"><b>Modeling and Characterization of Zero-Phase-Shift Lines (ZPSL) and Optimization of Electrically Large ZPSL Loop Antennas for Near-field Systems</b>（Published in: IEEE Transactions on Antennas and Propagation ( Volume: 64, Issue: 11, Nov. 2016 )</font></h3><h3><font color="#010101">Page(s): 4587 - 4594）<b><br><br>by Yunjia Zeng, Student Member, IEEE, Zhi Ning Chen, Fellow, IEEE, Xianming Qing, Senior Member, IEEE, and Jian-Ming Jin, Fellow, IEEE<br><br></b></font></h3> <h3><font color="#010101">Abstract:<br><br>A methodology for modeling and characterization of a zero-phase-shift line (ZPSL) structure is presented, and a ZPSL-based electrically large loop antenna is optimized for near-field wireless systems. The ZPSL loop is first analyzed with a full-wave driven-mode solver to obtain the dispersion curve. An equivalent circuit model is then presented for characterizing the ZPSL structure. Based on the dispersion analysis, a design guideline is proposed for the ZPSL loop antenna to enlarge its interrogation zone, where a uniform magnetic field distribution is desired. A design example at 915 MHz shows that the perimeter of the ZPSL loop antenna with a desired uniform magnetic field distribution can be optimized up to 2.5 operating wavelength, which is much larger than those reported with 2 operating wavelength, achieving a 56% increase in the area of the interrogation zone. The proposed method can be applied in the antenna design for near-field wireless systems such as wireless charging, radio-frequency identification (RFID), near-field communications (NFC), and magnetic resonance imaging (MRI).<br></font></h3> <h3><b><font color="#010101">Importance:<br><br>This work is a detailed and correct physical explanation of designs in Tech 5. Due to the single-wire structure, we can't use transmission line theory to model the structure for further study so that we don't know the upper bound of the electrical size of the loops. <br><br>With aid of dispersion analysis, we first proposed a currect and model the structure with high accurancy. With the analysis, we finally discovered the limit of the zero-phase shift loops and optimize the designs based on the new findings.</font></b></h3> <h3><b><font color="#010101">TECHNOLOGY 5</font></b></h3> <h3><b><font color="#010101">A: Control of near-zone magnetical field at UHF bands</font></b></h3> <h3><b><font color="#010101">IEEE Transactions on Antennas and Propagation?(Volume:58 ,??Issue: 12?)<br>Page(s):3829-3838<br><br><br>A Broadband UHF Near-Field RFID Antenn<br><br></font></b></h3> <h3><font color="#010101">A broadband segmented loop antenna is presented for ultra high frequency (UHF) near-field radio frequency identification (RFID) applications. Using a segmented line, the current distribution along the loop is kept in phase even though the perimeter of the loop is more than two operating wavelengths so that the proposed antenna generates strong and even magnetic field distribution in the near-field zone of the antenna. </font></h3> <h3><font color="#010101">?The antenna prototype, printed onto a piece of FR4 substrate, with an overall size of , achieves a large interrogation zone of with good impedance matching and uniform magnetic field distribution over the entire UHF RFID band of 840-960 MHz.</font></h3> <h3><b><font color="#010101">Importance:<br><br>With the introduction of capacitance into the thin - wire loop, the phase constant is reduced so that the phase along the wire hardly varied, that is, the electric current along the loop wire will propagate in the same direction even when the circumference of the loop wire is longer than jalf wavelength in free space. This type of current distribution will generate 1 uniform near-zone magnetic field in the loop area and 2 consistent far-zone radiation in planes where the loop is oriented in parallel.</font></b></h3> <h3><font color="#010101">After this paper, there have been many designs for UHF near-field RFID reader antennas, omnidirectional horizontally polarized radiation for WiFi and so on. We have reached 500×500mm consistent magnetical field coverage using single loop antenna.</font></h3> <h3><b><font color="#010101">B. Generation of Omni-directional Radiation with Horizontal Polarization</font></b></h3> <h3><b><font color="#010101">?An Omnidirectional Circularly Polarized Antenna Array<br><br><br>IEEE Transactions on Antennas?and Propagation, Volume:64 Issue:2, pp. 574-581, 2016</font></b></h3> <h3><font color="#010101">An omnidirectional circularly polarized (CP) antenna array is proposed. The antenna array is composed of four identical CP antenna elements and one parallel strip-line feeding network. Each of CP antenna elements comprises a dipole and a zero-phase-shift (ZPS) line loop. The in-phase fed dipole and the ZPS line loop generate vertically and horizontally polarized omnidirectional radiation, respectively. Furthermore, the vertically polarized dipole is positioned in the center of the horizontally polarized ZPS line loop. The size of the loop is designed such that a 90° phase difference is realized between the two orthogonal components because of the spatial difference and, therefore, generates CP omnidirectional radiation.</font></h3> <h3><font color="#010101">A 1 × 4 antenna array at 900 MHz is prototyped and targeted to ultra-high frequency (UHF) radio frequency identification (RFID) applications. The measurement results show that the antenna array achieves a 10-dB return loss over a frequency range of 900-935 MHz and 3-dB axial-ratio (AR) from 890 to 930 MHz. At the frequency of 915 MHz, the measured maximum AR of 1.53 dB, maximum gain of 5.4 dBic, and an omnidirectionality of ±1 dB are achieved.</font></h3> <h3><b><font color="#010101">Importance<br><br>Similar to Tech 5A, the current along the loop is consistent in terms of phase and amplitude. Such a current distribution will generate consistent far-zone radiation horizontally where the loop is oriented in parallel to a groud plane.</font></b></h3> <h3><font color="#010101">With similar design, antennas were also designed at 2.4GHz bands for industry products.</font></h3> <h3><font color="#010101">The 12 more papers presented at conferences are not listed here.</font></h3> <h3><b><font color="#010101">TECHNOLOGY 4</font></b></h3> <h3><b><font color="#010101">?IEEE Transactions on Antennas?and Propagation Volume:63 Issue:9?2015 pp.4156-4160<br><br>Broadband and Ultrathin Frequency-Dispersive Metamaterial Screen for Reflectivity Reduction<br><br></font></b></h3> <h3><b><font color="#010101">Importance:<br><br>We first proposed a frequency-dispersive magnetic material substrate for the ultra-thin broad bandwidth of metamaterial-based microwave absorber. </font></b></h3> <h3><font color="#010101">A frequency-dispersive magnetic material substrate is proposed to achieve the broad bandwidth of metamaterial screens for microwave absorption. Resonance-like ferrites with frequency-dispersive properties at resonant frequencies are applied as substrate. By mixing the multiple types of resonance-like ferrites, the desired bandwidth of frequency-dispersive magnetic material is further broadened. </font></h3> <h3><font color="#010101">Simulated and measured results show that the proposed metamaterial screen can operate from 7.9 to 14.6 GHz with the reflectivity of less than -10 dB with thickness of only 1.1 mm (0.029 λr,). A figure of merit (FoM) proposed to uate the absorption performance of the screen is 20.6 for the proposed screen.<br><br></font></h3> <h3><b><font color="#010101">TECHNOLOGY 3</font></b></h3> <h3><font color="#010101">The paper was published at IEEE Trans AP Vol 64 No 6 pp.1-6 June 2016.</font></h3> <h3><b><font color="#010101">Importance:<br><br>We first feed a dieletric resonator antenna (DRA) using Spoof Surface Plasmon (SSP)-based Transmission Lines (TLS) . Compared with conventional microstrip-fed DRA, the missed models are well excited by groundless SSP-TLS. This is also an important milestone to apply SSP concepts in antenna engineering.</font></b></h3> <h3><b><font color="#010101"> TECHNOLOGY 2</font></b></h3> <h3><b><font color="#010101">Importance:<br><br>We first model Spoof Surface Plasmon (SSP)-based Transmission Lines (TLS) using equavlent circuits. The proposed model is a necessary step for engineers to include SSP TLs in system design sofeware packages, for instance, ADS. This is also an important milestone to apply SSP concepts in microwave engineering.</font></b></h3> <h3><b><font color="#010101">paper:<br><br>Design and Modeling of Spoof Surface Plasmon Modes-Based Microwave Slow-Wave Transmission Line<br><br>IEEE Transactions on Microwave Theory and Techniques??(Volume:63 ,??Issue: 6?) 2015 pp. 1817 - 1825<br></font></b></h3> <h3><font color="#010101">This paper presents a theoretical model and validates experimentally the microwave slow-wave transmission line (SW-TL) based on spoof surface plasmon (SSP) modes. Equivalent circuit models are first presented for characterizing the SSP structures and developed to serve as an insightful guideline to design the SW-TL at a given cutoff frequency and Bloch impedance. </font></h3> <h3><font color="#010101">A mode converter connecting a conventional microstrip transmission line to the SW-TL is necessarily proposed to ensure that the quasi-TEM modes of the microstrip line are gradually transformed to the operating TM modes of the SW-TL. The presented schematic of SW-TL paves a promising avenue for the unprecedented interconnector footprint miniaturization of integrated circuits, and the enhanced electromagnetic compatibility, for example, in multilayered monolithic microwave integrated circuits.</font></h3> <h3><b><font color="#010101">TECHNOLOGY 1</font></b></h3> <h3><b><font color="#010101">Importance:<br><br>First, we use the metasurface as a ultra-low profile patch-like antenna with high gain across wide bandwidth rather than AMC, HIS, EBG, Superstrate/lens or high-permittivity loading.</font></b></h3> <h3><b><font color="#010101">paper 1<br><br>Metamaterial-Based Low-Profile Broadband Mushroom Antenna<br><br>?IEEE Transactions on Antennas?and Propagation?Volume:62 Issue:3?2014<br><br><br></font></b></h3> <h3><font color="#010101">A metamaterial-based broadband low-profile mushroom antenna is presented. The proposed antenna is formed using an array of mushroom cells and a ground plane, and fed by a microstrip line through a slot cut onto the ground plane. With the feeding slot right underneath the center gap between the mushroom cells, the dual resonance modes are excited simultaneously for the radiation at boresight. </font></h3> <h3><font color="#010101"><h3><font color="#010101">A transmission-line model integrated with the dispersion relation of a composite right/left-handed mushroom structure is applied to analyze the modes. The proposed dielectric-filled (εr=3.38) mushroom antenna with a low profile of 0.06λ0?( λ0?is the operating wavelength in free space) and a ground plane of 1.10λ0×1.10λ0?attains 25% measured bandwidth with(|S11| <; - 10dB) 9.9-dBi average gain at 5-GHz band. </font></h3></font></h3> <h3><font color="#010101">Across the bandwidth, the antenna efficiency is greater than 76%, and cross-polarization levels are less than -20 dB.</font></h3> <h3><b><font color="#010101">paper 2<br><br>IEEE Transactions on Antennas?and Propagation Volume:62 Issue:9?2014<br><br>60-GHz Thin Broadband High-Gain LTCC Metamaterial-Mushroom Antenna Array<br></font></b></h3> <h3><font color="#010101">Using the mushroom radiators, the single-element achieves high gain comparable to a 2×2 patch array but lower losses caused by the feeding network used in an array. This is vital important for the high gain antenna design where usually the antenna arrays suffer from high losses caused by feeding power dividers. Therefore, we use the proposed mushroom antenna as an element of array to reduce the feeding losses.</font></h3> <h3><font color="#010101">A low-profile broadband metamaterial-mushroom antenna array is proposed for high-gain 60-GHz band applications. The antenna array consists of a single-layer mushroom radiating structure and a simplified single-layer substrate integrated waveguide (SIW) feeding network. A new transmission-line based model is presented to estimate the resonant frequencies of the operating TM10 and antiphase TM20 modes. </font></h3> <h3><font color="#010101">An 8 × 8 mushroom antenna array is designed and prototyped using low-temperature cofired ceramic (LTCC), the measurement shows the antenna array with the feeding transition proposed an impedance bandwidth of 56.3-65.7 GHz with a boresight gain greater than 21.2 dBi and up to 24.2 dBi at 62.3 GHz. The proposed antenna array features the merits of high gain, broadband, compact size, and low cross-polarization levels.</font></h3> <h3><font color="#010101">篇頭的背景圖片，不是天線工程師設(shè)計的，但是是metasurfaces。想知道其中的故事嗎? 請看下面幾張照片。</font></h3> <h3><b><font color="#010101">朋友留言</font></b></h3> <h3><font color="#010101">南京大學(xué) 馮一軍:你們的工作推進(jìn)了超材料向應(yīng)用的轉(zhuǎn)換[Tongue]<br><br>南京大學(xué) 陳靜:<br>呵呵，異形同質(zhì)<br><br>北京中國傳媒大學(xué) 樸大志:<br>感覺這個第一波還沒怎么開始就結(jié)束了！<br>只有對超材料工作機(jī)理的深入理解和對傳統(tǒng)天線性能受限的本質(zhì)原因的揭示才可能提出有重大突破的結(jié)構(gòu)，you did it!<br><br>蘭州大學(xué) 牛調(diào)明:<br>陳教授的大作，而且是專業(yè)的，必須分享！[呲牙]<br>陳老師的團(tuán)隊好強(qiáng)大！[呲牙]<br><br>南京發(fā)小應(yīng)愛萍:<br>陳教授：創(chuàng)新高技術(shù)不要光介紹論文要感緊申請專利，否則就會變成別人的了，沒看到國內(nèi)磁材概念股炒翻天啦[調(diào)皮]<br><br>日本 佘元峰:<br>這篇論文貌似拜讀引用過[白眼]</font></h3> <h3><b><font color="#010101">我必須要感謝我的同事和學(xué)生們卓越的技術(shù)貢獻(xiàn)，精誠的團(tuán)隊協(xié)作和不懈的努力奮斗。有了他們才是我職業(yè)的最大成就。你會在陸續(xù)張貼的已發(fā)表論文中看到他們的名字，也拜托大家記住他們[抱拳]<br><br>當(dāng)然，我也銘記那些一直支持幫助我們相關(guān)工作的朋友們。無法一一列出，藉此告謝!</font></b></h3>